ref: replace `dvc run` examples with `dvc stage add` + `dvc exp run` or `dvc repro`

In the command reference, there are several examples using dvc run. Replacing these with dvc stage add may lead to clear examples.

• #3023
• #3031
• #3183
• #3070
• ref: Update index page
• ref: Update dvc run references in dvc gc
• ref: Update dvc run references in dvc import-url
• ref: Update dvc run references in dvc init
• ref: Update dvc run references in dvc metrics
• ref: Update dvc run references in dvc params
• ref: Update dvc run references in dvc plots
• ref: Update dvc run references in dvc repro
• #3103
• #3053
• ref: Update dvc run references in dvc status
• ref: Add a “deprecated” notice to dvc run ?

[jorgeorpinel]

I did take a look at getting started, and it seems like it will require more of an overhaul than just replacing text

Yeah let’s leave that to @iesahin for now then?

BTW I did find an existing issue that’s related so I’m updating it to follow up on all this: https://github.com/iterative/dvc.org/issues/2076

[jorgeorpinel]

Could the DVC team finish the cmd ref updates related to this @dberenbaum ?

@iesahin maybe we should just double check no other docs still use run unnecessrily.